Apparatus for the suspension of well bore devices



Oct. 1, 1968 v. c. H. RICHARDSON ETAL APPARATUS FOR THE SUSPENSION OFWELL BOREDEVIGES Filed Dec. 17, 1965 2 Sheets-Sheet 1 Y W I j i Verve/9CfiCQccr/QGOQ J? 2 6/40 6 ficz /ef' INVENTORS v ATTORNEY Oct. 1, 1968 v.c. H. RICHARDSON ETAL APPARATUS FOR THE SUSPENSION OF WELL BORE DEVICESFiled Dec.

2 Sheets-Sheet 2 INVENTORS BY MZW Afro/Flaw) United States Patent O3,403,728 APPARATUS FOR THE SUSPENSION OF WELL BORE DEVICES Vernon C. H.Richardson, Bellaire, and Billy G. Frazier, Houston, Tex., assignors toTransport Engineering, Inc., Houston, Tex., a corporation of Texas FiledDec. 17, 1965, Ser. No. 526,644 4 Claims. (Cl. 166-.5)

ABSTRACT OF THE DISCLOSURE Apparatus for use on floating vessels forcarrying out cable operations in Well bores located beneath the water tomaintain cable suspended equipment in the well at the same depth duringmovement of the vessel in response to wave action. The apparatusincludes a suspension cable for the equipment in the well and a mooringcable anchored at its lower end to a fixed location beneath the waterand yieldable pressure fluid means on the vessel having a movableconnection with each of the cables to apply a constant tension to thecables during the paying out and taking in of the cables duringmovements of the vessel due to wave action.

This invention relates to the carrying out of operations in well boresfrom floating vessels, and more particularly to mechanism for thesuspension of objects in well bores beneath the water and formaintaining the same at the same vertical location during movements of avessel in response to wave action.

In carrying out operations in well bores located beneath the water andparticularly such operations which require the maintenance of equipmentin the well at a predetermined depth great difliculty is oftenencountered due to wave action on the barge or other supportingstructure. Attempts have been made to overcome the effects of waveaction by mooring or by the provision of compensating apparatus tomaintain the vessel substantially stationary. Such equipment is,however, difficult to operate satisfactorily and'requires constantattention and maintenance.

The present invention has for its primary object the provision ofapparatus which is designed to support equipment in a well bore from afloating object and to maintain the equipment at the same depth in thebore during vertical movements of the vessel due to wave action.

Another object of the invention is to provide apparatus for use inconnection with cable suspension mechanism for rapidly paying out andtaking in cable in response to vertical movements of asupporting vesselto maintain the equipment suspended thereby at the same depth in a wellbore during movements of the vessel in response to wave action. I

A further object of the invention is the provision of cable suspensionapparatus for use with well equipment supported on a floating vesselembodying cable winding mechanism by which the equipment is suspended ina well from a vertically movable suspension means and means for movingsuch suspension means vertically in response to vertical movements ofthe vessel to maintain the suspension point of the equipment at the samelevel.

A still further object of the invention is the provision in cablesuspension apparatus of the kind mentioned of means whereby theequipment is maintained at the same vertical position in the well borewhile allowing variations in the vertical position of the suspensionpoint of the equipment without varying the length of cable which isunwound from the winding mechanism.

The above and other important objects and advantages of the inventionwill be apparent from the following de- 3,403,728 Patented Oct. 1, 1968tailed description of a preferred embodiment of the invention whenconsidered in conjunction with the annexed drawings wherein:

FIGURE 1 is a front elevational view of a drilling barge or other vesselshowing the suspension apparatus of the invention in position thereonand supporting well equipment in a well bore beneath the water;

FIGURE 2 is a fragmentary side elevational view, partly in cross-sectionof the suspension apparatus of FIG- URE 1, showing details of structureof pressure fluid mechanism forming a part thereof;

FIGURE 3 is a fragmentary side elevational view, partly in cross-sectionillustrating a modified form of the pressure fluid mechanism of theinvention; and

FIGURE 4 is a diagram illustrating the relative positions of the partsof the suspension apparatus assumed in response to changes in thevertical position of the supporting vessel due to Wave action.

Referring now to the drawings in greater detail the suspension apparatusof the invention is illustrated herein in connection with its use on abarge or other floating vessel, generally designated 10, of aconventional type, having a derrick 12 thereon which is provided withthe usual crown block 14 and travelling block mechanism 16 by which thewell equipment is suspended for the carrying out of operations in a wellbore indicated at B beneath the water.

Suitable cable winding mechanism 18 is provided on the vessel from whicha cable 20 leads over the crown block 14 to the travelling block 16 bywhich the suspension mechanism may be raised and lowered, and othercable winding mechanism 22 is provided on the vessel from which a cable24 leads to the well bore B and by which the equipment is suspendedtherein.

The suspension mechanism includes the suspension cable 24 with itswinding mechanism 22 and a mooring cable 26 which is connected at oneend at 23 to the vessel 10 and which is anchored at its other end 25 tosome stationary point, such as the well head equipment W or other fixedlocation.

The suspension mechanism also has pressure fluid means, generallydesignated 28, including a pressure cylinder 30, in which a piston 32 ismovably disposed, having a piston rod 34 to whose outer end sheavemeans'is attached comprising rotatably mounted pulleys 36 and 38 overwhich the cables 24 and 26, respectively, are passed. The piston rod 34is extended upwardly into an upper end tubular extension 40 of thecylinder 30 in which the rod is slidable to guide the same and preventtilting of the rod and piston relative to the axis of the pressurecylinder.

The pressure cylinder is carried in a closed outer casing 42 containinga suitable hydraulic fluid 44, above which the casing is pressurizedwith a suitable fluid, such as air, which may be introduced from anysuitable pressure source through an inlet pipe 46 under the control ofsuitable valve mechanism 48. The casing 42 is attached to the travellingblock 16, above, by any suitable means, such as that shown at 43, tosupport the suspension mechanism therefrom.

The cylinder 30 has ports 50 at its lower end through which hydraulicfluid 44 may flow into and out of the cylinder.

The casing 42 is provided with the usual safety valve 52 and pressuregauge 54.

In the operation of the suspension mechanism the well equipment issuspended at the desired location in the well on the cable 24, byoperation of the winding mechanism 22, the cable 26 being anchored atsome fixed location, as shown, and the pressure in the cylinder 30 beingadjusted so that the equipment is supported by the piston 32.

With the apparatus thus adjusted, the equipment in the well boreattached to the cable 24 will be maintained stationary during upward anddownward movements of the vessel in response to wave action, the cable24 being taken in over the pulley 36 during downward movement of thevessel and paid out thereover during upward movement of the vessel. Uponupward movement of the vessel, the cylinder 30 moves upwardly therewith,as does also the winding mechanism 22 of cable 24 and the point ofconnection 23 of the cable 26 with the vessel, so that the portion ofthe cable 24 between the pulley 36 and the equipment in the well becomeslonger, while the portion of cable 24 between pulley 36 and the windingmechanism 22 becomes shorter. Similarly the portion of cable 26 betweenpulley 38 and the well head W becomes longer while the portion of cable26 between pulley 38 and the point of connection 23 becomes shorter.

Moreover, as the vessel moves upwardly, carrying with it the cylinder30, the hydraulic fluid beneath the piston 32 is forced out throughports 50 into the casing 42, compressing the pressure fluid thereinabove the hydraulic fluid to maintain the tension on the piston rod 34,whereby the tension on the cables 24 and 26 is maintained.

Upon downward movement of the vessel the connection point 23 and cablewinding mechanism move downwardly therewith to length the portion ofcable 24 between the pulley 36 and winding mechanism 22 while shorteningthe portion of cable 24 between pulley 36 and the equipment in the wellbore. The portion of cable 26 between pulley 38 and connection point 23is also lengthened while the portion of cable 26 between pulley 38 andconnection point 25 is shortened. Such downward movement of the vesselalso results in downward movement of the cylinder 30, so that hydraulicfluid in casing 42 under the pressure of the pressure fluid thereaboveis forced into cylinder 30 beneath the piston 32 to maintain the tensionon the cables to prevent any slackening of the same.

FIGURE 4 illustrates diagrammatically the operation of the apparatusduring upward and downward movements of the vessel. As seen at the leftin FIGURE 4 the vessel is in a lower position L, and under theseconditions the cylinder 30 is in a lowered position relative to thepiston 32, the portions of cables 24 and 26 designated AB beinglengthened while portions thereof designated BC are correspondinglyshortened. Centrally in FIG- URE 4 the vessel is Seen in an intermediatevertical position M of its movement, in which the cylinder 30 is shownat a somewhat higher position relative to piston 30, the cable portionsAB being now somewhat shorter than in the power position of the vesselwhile portions BC are correspondingly lengthened. At the right of FIGURE4 the conditions prevailing when the vessel is in an upper position areshown, the cylinder 30 being now in a higher position relative to piston32 while portions AB of cables 24 and 26 are more shortened and portionsBC thereof are more lengthened. It will be apparent however that in allpositions of the apparatus and the vessel, the sum of the portions ABand BC cable 24 is the same, as does also the portions AB and BC ofcable 26, as shown in the lower diagram of FIGURE 4, and the position ofthe equipment in the well attached to cable 24 remains unchanged.

A somewhat modified form of the pressure cylinder mechanism of theinvention is illustrated in FIGURE 3, wherein the casing 42 issurrounded by a closed annular chamber 58 upon which suitable compressormechanism generally designated 60 of a conventional type is mounted. Thecompressor 60 has a discharge line 62 which leads into the chamber 58through which the chamber may be pressurized to the desired pressure. Asupply pipe 64 leads from the chamber 58 into the interior of the casing42' near the top of the casing to pressurize the casing above thehydraulic fluid therein. The chamber 58 thus forms a pressureaccumulator from which fluid under pressure is supplied to the casing 42to replenish the pressure therein and to vary the pressure applied tothe cylinder 30'. The chamber 58 has a relief valve 52", which is set toopen at a higher pressure than the relief valve 52' of the casing 42, sothat a higher pressure will be built up in the accumulator chamber 58than in the casing 42'.

A supply pipe 64 leads from the chamber 58 into the casing 42' under thecontrol of an adjustable regulator, which may be set to maintain thepressure in the casing 42' at a desired pressure. In other respects thepressure cylinder mechanism of FIGURE 3 is like that of FIG- URE 2, andoperates in a similar manner.

By this arrangement, upon a downward movement of the piston 32 incylinder 30 pressure will be applied to the pressure fluid in casing 42above the hydraulic fluid therein, to open valve 52' whereby thepressure in casing 42 will be maintained constant. Upon upward movementof the piston 32' in cylinder 30' the pressure on the pressure fluid incasing 42 above the hydraulic fluid will be reduced whereupon fluid fromaccumulator chamber 58 will flow into casing 42' through pipe 64- tomaintain a constant pressure in the casing, whereby the forces actingupon the piston 32 are maintained substantially constant at all times.

It will thus be seen that the invention constructed as disclosed hereinprovides suspension mechanism for use in supporting equipment in a Wellbore beneath the water from a floating vessel and by which the positionof the equipment in the well can be held at the desired depth regardlessof the movements of the vessel in response to wave action orfluctuations in tide.

The invention is disclosed herein in connection with certain specificembodiments of the same, which it will be understood are intended by wayof illustration only, it being apparent that various changes in theconstruction and arrangement of the parts may be made within the spiritof the invention and the scope of the appended claims.

The invention, briefly described, comprises a suspension cable andwinding mechanism therefor supported on a floating vessel so that thesuspension cable may be used to support equipment in the bore of a welllocated beneath the water, and a mooring cable whose upper end isfixedly attached to the vessel and whose lower end is fixedly anchoredat a location beneath the water. Both of the cables pass over pulleysyieldably supported on the vessel to allow the cables to be paid outover the pulleys upon upward movement of the vessel due to wave actionand taken in upon downward movement of the vessel due to such action.The yieldable means by which the pulleys are suspended includes a hollowcasing suspended from above on the vessel and a cylinder in the casingwhose upper end is closed and whose lower end is closed by the bottomwall of the casing, the cylinder having openings adjacent its lower endthrough which liquid in the casing may flow into and out of thecylinder. A piston is movably disposed in the cylinder and has a pistonrod slidably extended through the bottom wall of the casing which rod isconnected to the pulleys and means is provided for applying pressure tothe liquid in the casing to apply a yieldable tension to the cables inresponse to vertical movements of the vessel.

Having thus clearly shown and described the invention, what is claimedas new and desired to be secured by Letters Patent is:

1. Apparatus for suspending equipment in a well bore beneath the waterfrom a floating vessel comprising:

a suspension cable connected to the vessel and extending into the wellbore;

a mooring cable connected to the vessel and to a fixed location;

tensioning means comprising an elongated hollow casing, means forsuspending the casing at one end above the vesel, a cylinder in thecasing extending 5 axially thereof whose upper end is closed and whoselower end is closed by the lower end wall of the casing and formedadjacent its lower end with openings through which fluid in the casingmay flow into and out of the cylinder, a piston slidably disposed in thecylinder, a liquid in the casing and in the cylinder beneath saidpiston, and means slidably eX- ten-ded through the lower end wall of theeasing into the cylinder and means forming a movable connection betweenthe piston and each of said cables to apply a tension to the cables inresponse to vertical movement of the vessel.

2. The apparatus as set forth in claim 1 wherein said connecting meansincludes rotably mounted pulley means over which said cables pass.

3. The apparatus as claimed in claim 1, wherein said casing is movablysupported on the vesel for movement to a position to move the piston toa predetermined location in the cylinder when a predetermined tension isapplied to the cables.

4. The apparatus of claim 1 wherein said tensioning means includes meansfor applying pressure to the liquid in said casing to maintain aconstant pressure of fluid in the cylinder.

References Cited 7 UNITED STATES PATENTS 2,945,677 7/1960 Kammerer 17553,001,396 9/1961 Cleveland 254188 3,158,206 11/ 1964 Kammerer 175-53,158,208 11/1964 Kammerer 175-5 3,208,728 9/1965 Parks 166-75 3,276,74610/ 1966 Berne 175-5 3,285,574 11/1966 Berne et al. 254-172 JAMES A.LEPPINK, Primary Examiner.

